1970's MODCOM dispatch console

[firedog359]

Hello everyone,I recently picked up a 70's era MODCOM dispatch console from a county communications center her in NC.It had sat in the basement boiler room for a long time so it was pretty filthy.I have managed to get it halfway cleaned up and all of the cards pulled from the cages.My goal is to restore it to a point where I can power it up and at least make all of the lights work.There is what appears to be a DC-DC power supply mounted in the back but I'm not sure.There are two heavy guage black and red cables run to it and no other power cords.There is a small factory installed 120 volt receptacle strip but nothing is plugged in.I am hoping that someone can tell me how this console actually worked,what the differnt cards are,how the power system works and any other info available.i really would like to find the manuals for it. I am posting links to my photos of the console. I want to thank everone who has replied to my other posts about other equipment.All of you have been so very helpful and it is greatly appreciated.I hope that someone can help me on this one.

http://imageshack.us/a/img585/3648/modcom001.jpg
http://imageshack.us/a/img32/3859/modcom002.jpg
http://imageshack.us/a/img534/918/modcom003.jpg
http://imageshack.us/a/img401/9715/modcom004.jpg
http://imageshack.us/a/img842/3231/modcom005.jpg
http://imageshack.us/a/img171/8136/modcom006.jpg
http://imageshack.us/a/img59/4348/modcom007.jpg
http://imageshack.us/a/img62/5463/modcom008.jpg

[firedog359]

I see that i have not recieved any help on this.I hope that it's because no one has any info and not because I've worn out my welcome on the forums.I know that I'm not a ham or a radio tech like a lot of you.I'm just a Firefighter who loves old radio equipment and is trying to preserve some of the stuff from "the good old days" and you guys are the only ones I have to turn to for help.So please bear with me.Thanks

[d119]

By no means whatsoever have you "worn out your welcome", please stop self-deprecating! You are welcome here, 100%!

I moved your post to the Infrastructure forum in hopes of getting some more information to you.

Whatever it is, it's TOTALLY COOL! I cut my teeth on Centracom II+, so it's a bit before my time.

Would love to see pictures after it's cleaned up.

It appears the power supply is there.... Have you tried putting 12V DC on the red/black leads?

The box with the big silver "BKNxxxx" plugs plugged into it appears to be the power supply. Is there no AC cable coming out of it anywhere? Check closely.

[Bill_G]

You're probably not going to get it to fire up, though it may catch on fire. The caps have probably dried out. I've never seen this before, but it looks like it was based on the CC1 concept where all the electronics were in the console on the cards, not in the back in a rack. TTL logic along with a lot of RTL (resistor transistor logic). The dialer on the front suggests it was in a hospital. Without schematics, it will be difficult to get functioning. If it uses the riveted eyelet circuit boards, I guarantee it will be intermittent. You can buff it up and make it pretty, but I wouldn't try to restore it.

[Jim202]

Not sure, but I think the right side of the console looking from the back is where the line modules plug in. Those screw terminals I think are where the telephone remote wires get connected. It wasn't that clear in the photos, but it looked like a couple of them might have had some wires connected to them. Could be wrong in my guess. Been a long time since I have seen anything like that.

Take a look around and see if it has an AC power supply to feed the DC voltage to the console. Again the photos didn't show that much detail. I did see the heavy DC wires leaving the console. It could have been powered externally and as such didn't have an internal AC to DC supply.

The age of that thing would put it into the DC remote control. Tone didn't come into play until much later in time. There was probably a DC control module for each channel in the console. This is the location where the telephone wires would have been connected. You would have a choice of 2 wire or 4 wire connections. Most of the time a 2 wire connection was used to save the cost of the rental on the more expensive 4 wire circuits of the day. In other words you would have to rent 2 circuits, one for the TX and one for the RX sides. Not too many places back then used a microwave system due to the cost. Just very large agencies could afford the microwave.

Jim

[firedog359]

The dialer was part of the old intercity LE system.It was a base to base system operating on 155.190,no PL.It used the SeCoDe dialup system.The encoder emitted a 2805 tone interupted by the appropriate 4 digit code corresponding to the decoder number of the dept being contacted.It was also used for ambulance to Hospital traffic.Each hospital had a specific 4 digit decoder number.This console is using (3) BLN1029A transmit cards,(3) BLN6088B-2 and -3 mute cards,(1) BLN1020A intercom/simul/all mute/alert card,(1) BLN1039A region/TX w/o PL/emgcy card,(1) Q1616A dialer,(1) BLN1031A mute card,(1) BLN1045A card marked call/mute,busy/select,and xmit.(2) BLN1028A speaker cards,and (1) BLN1039A which is unidentified.It is a short card that is covered by a filler plate and has to pulled out with an attached tab.As far as the power,the red and black cables are the only power cables that I can see.I have not applied any power to them due to not knowing the voltage/amp requirements.

[firedog359]

Here are some additional photos.i hope they help.thanks
http://imageshack.us/a/img844/3231/modcom005.jpg
http://imageshack.us/a/img96/9715/modcom004.jpg
http://imageshack.us/a/img713/918/modcom003.jpg
http://imageshack.us/a/img705/3859/modcom002.jpg
http://imageshack.us/a/img163/3648/modcom001.jpg
http://imageshack.us/a/img19/3648/modcom001.jpg

[Jim202]

Here are some additional photos.i hope they help.thanks
http://imageshack.us/a/img844/3231/modcom005.jpg
http://imageshack.us/a/img96/9715/modcom004.jpg
http://imageshack.us/a/img713/918/modcom003.jpg
http://imageshack.us/a/img705/3859/modcom002.jpg
http://imageshack.us/a/img163/3648/modcom001.jpg
http://imageshack.us/a/img19/3648/modcom001.jpg

If you look at photo 001 above, you will see a piece of the gray JK telco cable coming off the back plane. that should be your connection to go between the console and the remote radio.

It also looks like you may have 3 or 4 of the line cards to control the remote radios. I think those are going to be the one with the large transformer near one end of the board.

Power should be a normal 12 volt supply (13.5 volts or so) with the red being plus and the black being negative. If you use a ohm meter, I would see if you get zero ohms or something real close from the black wire to the metal part of the chassis where those 2 wires go into. I don't think they used a floating ground in that console.

Hope you kept track as to where all the cards went that you pulled out. Putting them in the wrong slots might cause you to get highly ticked off when the power gets applied.

I have used 2 products to clean up equipment in the past. One is Windex and the other is 409. Be a little careful on the paint you don't want to damage when using the 409. I have seen it take off some of the cheap paint at times. I wouldn't let the product stay very long on any surface. Spray and wipe without it staying on one spot. It doesn't take much to clean grime off of most surfaces. Just using some of the household paper towels or the blue automotive towels will work wonders for you.

Jim

[PETNRDX]

I have been following this thread while attending IWCE.
So, was not able to look at my manuals until today.
I only found a couple of those circuit board numbers in my couple books so far. Nothing useful.
That is a pretty cool old console. Wish it was mine...
Probably going to be a major project to get that thing going.
May just have to fake up a couple circuits to use it as a "working prop".
The numbers look older than my Centracom Series manual dated 1976.
I disassemble those sort of things and wash the console cabinets and plates with a hose and 409.
Even the trays and backplane circuit boards.
I try to do the circuit boards them selves separate, and only spritz them. Leave them in the sun to dry for an hour.
Face plates with 409 or ivory bar soap and a toothbrush.
As I said, if you were close, I would try to rush over and talk you out of it.

[firedog359]

Thanks for checking your manuals.I have started the cleaning process.This console has three seperate cages with the cards in them and there appears to be one wire between each cage interconnecting them down to the tone remote board.The connections on the main circuit boards are pin and sleeve so it's simple to disconnect and reconnect them and the main harness's just unplug from the power supply.I guess like the name implies,this console is pretty modular.The only problem I've run into is when I pulled the center cage,The transmit/monitor switch leads pulled loose from the board and I have no clue what pins they were on.I know this is not a big deal with the console being a display only but I still like to have everything hooked up and working.

[RF Geezer]

Robert
For you and all here

I have located our MODCOM console racks back in the ware house. They were found hidden away on a top shelf. As inspected briefly, most are SP or Special Product versions of the standard MODCOM console equipment. We will pull them down from the top shelf for further inspection. (Think Palletized shelving)

One shelf has a BLN6088A-2 tagged Mute Board

Our old sales book from 3-1-73 shows limited product information. Only the BLN1029 was identified.BLN1029 DC Transmitter Control Module.

Some cards to look for:
B1204 Multistation Control Panel includes microphone, clock 2 speakers w vol controls VU meter, Dual Pedal foot switch w/indicator, PL Monitor, Head Set Jack, Alert Tone, Intercom, Simul Select, low voltage Power Supply, High Voltage Power Supply
B1205 Transmit Module with Select and XMIT buttons
BLN1026 Tone Transmitter Control Module
BLN1029 DC Transmitter Control Module.
B1206 Receiver Control Module with call indicate and Mute switch
At least one TX and one RX module are needed to make the B1204 Control Panel operative.
B1207 half panel module mount
B1208 Speaker/Amplifier Module with volume control
B1209 " " with notch filter
B1300 Module Mounting Rack
B1301 Utility Switch Module
BPN1000 Low Voltage P.S.
BPN1001 High Voltage P.S.
BLN6108 Supervisory Control Kit
BLN6107 Main/Standby Line transfer kit
BLN6109 24 Hr clock
K159AA Tone Control modification Kit
BLN6117 Tone Accessory Switch Board
BLN6118 Tone Accessory Function Switch & Indicator Board
Q1651A Push Push 4 Switch Module

There are a host of calling options, Digital dialer (HEAR EMS Radio), Quick call I 2+2 tone format, and single tone encoders as well. Decoder options existed as well.
Hardware: 24 and 32 switch Illuminated status slot panels, Dual Card Rack, 12 and 24 Hour Time Stamp, RR crossing and bridge indicator, 24 light kit and several illuminated status options.

I will look through our old manual stock pile. I don't recall having the MODCOM books, but after 35- 40 years I can't remember. It very well might be there!

We will do what we can for you.

Regards.

Brad Mechem

> -----Original Message-----
> From: [email protected]
> To: [email protected]
> Date: 03/17/13 00:46
> Subject: Contact Us Requested

[firedog359]

Thanks for all of this info.I was cleaning the console and when I pulled a rack I found the original product performance report/quality postcard that was never sent back to Motorola.The model and PO #'s are written in red ink and very faded but I can tell the model # begins in B and has a 4 digit number ending in 04.That's about it.This console is pretty close to the B1204 description but has a few differences.Mine doesn't have the foot pedal,the transmit/monitor switches are under one of the front panels,nor does it have the headphone jack.It does have the phone type dialer for what I have been told was the old Intercity LE dialup system on 155.190 and for ambulance to hospital use.There is a small red 4 segment display underneath one of the panels but I'm not sure it's a clock.All of the function cards have BLN numbers on them and I haven't seen any of the B numbers although they may be there.I really hope to find some manuals for this.there are wires that are not connected to anything and as I posted earlier,I pulled the transmit/monitor switch leads off the board and don't know what pins they were attached to.As far as the power supply,I don't think it has one installed.i took the unit out that has the heavy black/red cables and the backplane harnesses plugged into it but it appears to be just a power distribution board.It is marked BLN6128.Thanks to all of you for the information and help on this console.it is greatly appreciated.

[firedog359]

Would anybody know what the voltage/amp requirements for this console are? I have been told that it requires two different power supplies,a low voltage and a high voltage.

[RF Geezer]

Robert


I have located one of the MODCOM power supplies in the warehouse. I placed the BPN1000B on the bench and brought it up to 120 VAC via Variac. There is a single 24 VDC output. This supply powers the console but a separate HV supply is needed for DC keying. It provides 175 VDC, with various current configurations for F1 TX, PL knock down, F2 etc.


I have reviewed your photo's and find something of interest. To the left of the Rotory 2805 Hz dialer there is a CentraCom I T/R module. Take a look at that card for BLN1045A/BLN1128A Id numbers. This card may be used for DC keying with a DC regulator option board. It may also be used for Tone Keying with the card you already have. The Tone Key Module has the plastic wire tye card puller attached. The standard model will be BLN1044A or a patch model BLN1051A. It appears you have option boards on top of the Tone Key Module. BLN1049A Tone Frequency Board (Y Bus) BLN1050A Tone Frequency Board (X Bus) and the BLN6236A F3/F4 board with the Coil on top.


You would appear to have a mix of MODCOM and Centracom I. All run from 24VDC. The HV supply may have been removed with the addition of the Tone Key Equipment.


On the MODCOM back plain there is a HV on /off switch. There is a 24 pin F/M black phenolic connector similar to the Motrac M series equipment, from the same era. It may very well tie into the BLN6113A power distribution panel we have. Look for a panel in your equipment with 9 fused outputs with 9 of the same 24 pin connectors. The panel would be fed by the BPN1000B 24 VDC supply.



On your back plain to the left, look for PC runs with 2 pins Etched HV and HVC. This is where any HV supply would be fed to for DC Keying. Tracing the wires back to a connector would verify your HV path way. With the BLN1029A MODCOM DC Keying modules you have in place would require the HV to send DC keying currents down the line.



Conjecture. Perhaps the original MODCOM system was all DC Keying. Adding the CI cards would give at least one Tone Keying line to a remote Base Station. The system may have been a mixture of DC and Tone controlled stations. (Not that any service folks have ever seen a mixed bag of worms under the hood!)



Applying 24 VDC to feed the console, the Tone Keying Encoder output may be quickly located with a scope or Telco But set.



I have one more location to check for MODCOM manuals. I will check when I have a little time. Service work is calling!



Brad Mechem

Mechem Electronics Inc

[firedog359]

Hello all,First and foremost I want to thank all of you for all the great help and information that you have provided on this console.You are the best.When I aquired this console my intentions were to refurbish it and make it work again.I have come to the conclusion that I have neither the time nor the expertise to accomplish this.I am a top notch electrician but I am no radio/electronics tech and I don't have the diagnostic equipment needed for this type of work.In addition,there are no radio/electronic techs in my area that know anything about this console that I could take it to for help.So,I have decided to sell the console in the hopes that someone else can do what I can't.As I am a newbie here,I can't list anything for sale on here so I have listed it on Ebay.Due to the size and weight it will be pickup only.I hope that someone who has helped with info and advice will be the buyer but we'll have to see.Again,Thanks for all your help.